diff --git a/Changes b/Changes
index c2e5d570d..3eca09ece 100644
--- a/Changes
+++ b/Changes
@@ -3,6 +3,11 @@ Revision history for Verilator
 The contributors that suggested a given feature are shown in [].  [by ...]
 indicates the contributor was also the author of the fix; Thanks!
 
+* Verilator 3.84***
+
+***   Support "unsigned int" DPI import functions, msg966.  [Alex Lee]
+
+
 * Verilator 3.843 2012/12/01
 
 ***   Add +1364-1995ext and similar language options, bug532.  [Jeremy Bennett]
diff --git a/src/V3Ast.h b/src/V3Ast.h
index 1fba0213e..6e2c6e627 100644
--- a/src/V3Ast.h
+++ b/src/V3Ast.h
@@ -356,6 +356,9 @@ public:
     bool isDpiUnsupported() const {
 	return (m_e==LOGIC || m_e==TIME);
     }
+    bool isDpiUnsignable() const {  // Can add "unsigned" to DPI
+	return (m_e==BYTE || m_e==SHORTINT || m_e==INT || m_e==LONGINT || m_e==INTEGER);
+    }
     bool isOpaque() const {  // IE not a simple number we can bit optimize
 	return (m_e==STRING || m_e==SCOPEPTR || m_e==CHARPTR || m_e==DOUBLE || m_e==FLOAT);
     }
diff --git a/src/V3AstNodes.cpp b/src/V3AstNodes.cpp
index 05876bab1..a3e37f36f 100644
--- a/src/V3AstNodes.cpp
+++ b/src/V3AstNodes.cpp
@@ -268,6 +268,9 @@ string AstVar::dpiArgType(bool named, bool forReturn) const {
 	}
     } else {
 	arg = basicp()->keyword().dpiType();
+	if (basicp()->keyword().isDpiUnsignable() && !basicp()->isSigned()) {
+	    arg = "unsigned "+arg;
+	}
 	if (!forReturn && isOutput()) arg += "*";
     }
     if (named) arg += " "+name();
diff --git a/test_regress/t/t_dpi_import.v b/test_regress/t/t_dpi_import.v
index a372488ce..bb4cd6181 100644
--- a/test_regress/t/t_dpi_import.v
+++ b/test_regress/t/t_dpi_import.v
@@ -56,6 +56,10 @@ module t (/*AUTOARG*/
    import "DPI-C" pure function void dpii_v_chandle  (input chandle   i, output chandle   o);
    import "DPI-C" pure function void dpii_v_string   (input string    i, output string    o);
    import "DPI-C" pure function void dpii_v_real     (input real      i, output real      o);
+
+   import "DPI-C" pure function void dpii_v_uint     (input int unsigned i,      output int unsigned o);
+   import "DPI-C" pure function void dpii_v_ushort   (input shortint unsigned i, output shortint unsigned o);
+   import "DPI-C" pure function void dpii_v_ulong    (input longint unsigned i,  output longint unsigned o);
 `ifndef NO_SHORTREAL
    import "DPI-C" pure function void dpii_v_shortreal(input shortreal i, output shortreal o);
 `endif
@@ -92,6 +96,9 @@ module t (/*AUTOARG*/
    byte		i_y,	o_y;
    shortint	i_s,	o_s;
    longint	i_l,	o_l;
+   int unsigned		i_iu,	o_iu;
+   shortint unsigned	i_su,	o_su;
+   longint unsigned	i_lu,	o_lu;
    // verilator lint_off UNDRIVEN
    chandle	i_c,	o_c;
    string 	i_n,	o_n;
@@ -120,9 +127,12 @@ module t (/*AUTOARG*/
       i_b96 = {1'b1,wide[96-2:0]};
 
       i_i = {1'b1,wide[32-2:0]};
+      i_iu= {1'b1,wide[32-2:0]};
       i_y = {1'b1,wide[8-2:0]};
       i_s = {1'b1,wide[16-2:0]};
+      i_su= {1'b1,wide[16-2:0]};
       i_l = {1'b1,wide[64-2:0]};
+      i_lu= {1'b1,wide[64-2:0]};
       i_d = 32.1;
 `ifndef NO_SHORTREAL
       i_f = 30.2;
@@ -160,6 +170,9 @@ module t (/*AUTOARG*/
       dpii_v_byte     (i_y,o_y); if (o_y !== ~i_y) $stop;
       dpii_v_shortint (i_s,o_s); if (o_s !== ~i_s) $stop;
       dpii_v_longint  (i_l,o_l); if (o_l !== ~i_l) $stop;
+      dpii_v_uint     (i_iu,o_iu); if (o_iu !== ~i_iu) $stop;
+      dpii_v_ushort   (i_su,o_su); if (o_su !== ~i_su) $stop;
+      dpii_v_ulong    (i_lu,o_lu); if (o_lu !== ~i_lu) $stop;
       dpii_v_chandle  (i_c,o_c); if (o_c !== i_c) $stop;
       dpii_v_string   (i_n,o_n); if (o_n != i_n) $stop;
       dpii_v_real     (i_d,o_d); if (o_d != i_d+1.5) $stop;
diff --git a/test_regress/t/t_dpi_import_c.cpp b/test_regress/t/t_dpi_import_c.cpp
index 2841b6414..02dcfb91f 100644
--- a/test_regress/t/t_dpi_import_c.cpp
+++ b/test_regress/t/t_dpi_import_c.cpp
@@ -52,9 +52,12 @@ extern "C" {
 
     extern void dpii_v_bit	(unsigned char i, unsigned char* o);
     extern void dpii_v_int	(int i,		int *o);
+    extern void dpii_v_uint	(unsigned int i, unsigned int *o);
     extern void dpii_v_byte	(char i,	char *o);
     extern void dpii_v_shortint	(short int i,	short int *o);
+    extern void dpii_v_ushort	(unsigned short i, unsigned short *o);
     extern void dpii_v_longint	(long long i,	long long *o);
+    extern void dpii_v_ulong	(unsigned long long i, unsigned long long *o);
     extern void dpii_v_chandle	(void* i,	void* *o);
     extern void dpii_v_string   (const char* i, const char** o);
     extern void dpii_v_real     (double i,      double* o);
@@ -93,9 +96,12 @@ float		dpii_f_shortreal(float i)	{ return i+1.5; }
 
 void dpii_v_bit	(unsigned char i, unsigned char *o)	{ *o = SV_MASK(1) & ~i; }
 void dpii_v_int (int i, int *o)				{ *o = ~i; }
+void dpii_v_uint (unsigned int i, unsigned int *o)	{ *o = ~i; }
 void dpii_v_byte (char i, char *o)			{ *o = ~i; }
 void dpii_v_shortint (short int i, short int *o)	{ *o = ~i; }
+void dpii_v_ushort (unsigned short i, unsigned short *o) { *o = ~i; }
 void dpii_v_longint (long long i, long long *o)		{ *o = ~i; }
+void dpii_v_ulong (unsigned long long i, unsigned long long *o)	{ *o = ~i; }
 void dpii_v_chandle (void* i, void* *o)			{ *o = i; }
 void dpii_v_string   (const char* i, const char** o)	{ *o = i; }
 void dpii_v_real     (double i,      double* o)		{ *o = i + 1.5; }